Dynamo-electric machine adapted for synchronous working



DAPTED FOR SYNGHRONOUS WORKING- DYNAMO EL 7 Sheets-Sheet 2 WORKING" 'DYNAMO ELECTRIC .if

Shams-Sheet Juiy 24, 1923- 1,463,017

iJ. HUNT n DYNAMO ELECTRIC MACHINE ADAPTED FOR SUSCHHONOUSl WORKING Fld Apri?. 19. Ql '7 Sheets-Shea?l 5 l: rf: Pfl/Q, ich

:www l1 imm if my 24, w23;- y 1,463,017

L. J. HUNT DYNAMO ELECTRIC MACHINE ADAPTED FOR SYNCHRONOUS WORKING 4 Poi@ ZPole /A/Vf/Wa/e @fx @5mm um?,

mi. with those of Figure 5, andi inflow ol1 the currents uruier those isc diagram oic the same winding connections c anged to enable "i to be produced.

u lcy diagram corresponding 'iO is e diagram oi' a stator wiiidanni oi :i change vpole switch therefor,

Led for use iu :my crise Where only 'the il, numbers are requircti to be proie iel. i lci diagram showing lio?? "Moos varies to produce u is a diagram of the rot-or en@ gs, :me of u. change pole svitci'i and synch' musing coutrojer, or eiieoli the nciirorious forrcspoudi also :it the simiior diagram o'" ctions arranged to c corL rfpoufiiugg to not at i und i' leading' to opposite gom 5@ iu the Winding. rlie Generator is siiow'o au.

j .vu u

lm ig series field i its terminal f; being connected to slip ring), and terminal 7i to slip rings T. The current Hows as indicated by the arrows, and by the crosses and dots 55 ou the bers, so as to produce a pole field. ,is is seen from the key diagrams, Figures und 3, tile current entering 7 iiivifles paths, the one tiziourli coils 5, i the mm gli colis f5, if/ l coils obtain trie resultents inciicated by the numbers above the circles in the line u above the diev'im, Figure l. l't will be eeen that the dist ibutioii is syimuetriczrl, and is satis'actory for the purpose in View, H 110W the Winding of the stator of this machine has alternating current supplied to it so as to produce e L-pole field, the machine will operate :is a synchronous motor at i-pole speed. it is assumed that the stator has windings arranged to produce ields of the two basic pole numbers for which the rotor .is designediii this instance 2 and Ll poles.

the coils 3, 5, 9 and ll in the rotor Winding; which csi-ry .no current at the synchronous speed, are interconnected in pairs as in Figure for example, and fis indicated by dotted lilies Q0 and 2i in Figure 1, it virilibe seem. that these connections will not interi? re wiii 'tlic 'iow of the current from the euerotor o lieceuse the slip rings 3 and, il, ind die siip rings and i), are equipotentiei `ioiuts with res )ect to the direct current circuit. The connections so compieteci however provide closed circuits through some of the coils in which currents will be induced mining to the unbalanced Whenever the machine tends to go out of synchronism, and these currents produce fields tending. to pull the rotor into syuchronism again. In fact, in a machine having these local circuit paths pioif'idexl by the interconnection of the slip rings 3 and 1l, 5 and 9 as above, no tendency whatever to hunt or to go out of synchroriisii can be detecteci. i

Figures and 6 .show un alternative iuietiiocl of interconnecting the slip rings 3, 3, S il, so es to provide closed damping circuits, and to .filiow of the flow o diiirougii their coils. In this case and 5 are connected through hing moons 22, snol the coils d. et and the iow 'gli iu coils and Y be y 7.2, 6 and B, wiil curry mirror s i the velue 3; again, iic coii'uctmice of the with through the coii or coil l() is twice Ithat of the path through the coiis 3 and 5, or 9 and l-forming' a parailel connection, the currents in coils Il and 10 will be of the value 2, while those in coils 3, 5, 9 and 'll will be of the value l. The currents in coils in some of the slots will neutralize one :mother in part, but the resulent currents indicated by the values above the circles iu the line u, Figure (E, ai symmetrically distributed and efielii. .other more current is sume m-ctive field than with u' ie iii i'igguie 4l, owing in certain Elli lill

those provided by the connections made at 20 and 2l in Figures l and fl.

Referring now to Figures 7 and 8, it will he seen how the connections of the rotor winding are changed when the held corres pondiiip,` to the other basic pole number, in this example the 2-po1e held, is to he produced. The slip rings l and l are connected together, and to one terminal 7ioi' 'the generator, by a connection 2e, while the other terminal g of the generator leads to a connection 25 joining the reniaiming` four slip rings and coils 3, 5, 9 and ll in parallel. As the ends of the coils si and l0 are equipotential points with respect to the direct current circuit, they carry no current synchronism, although they form part o the local dampingf circuits in which currents can flow tending to maintain synchronism. The currents in coils l and 7 are of twice the value of those in coils 2, 3, 5, 6, 8, i), ll and 12, but as is seen in the diagram Figure 7, the coils l and T occupy the same slots as coils iand l() which carry no current. ln our other slots the currents in the coils add their effects, but in the Qnrhrd, lith and 9th slots the currents oppose and neutralize the eiiects one oit another; the resultant held indicated by the figures above the circles in line u, Figure i', is symmetrically distributed and complies with all practical requirements.

lt will thus he seen that a machine haring a Winding as in Figures l to 8 can be made to cio-operate with stator producingu rotating fields or" 4 poles and 2 poles respectively, so as to run as a synchronous motor at' two di'erent speeds, the one twice as as the other. ll' the basic pole numbers were 8 and 'l2 of course the speed ratios would he 2 3, which corresponds to what is most usually required in practical applications o'r the invention.

leferringnow to Figure 9, it will be seen that this illustrates two windings, the inner one a ole windin r with a star connection D at All, and with terminals indicated as receiving alternating current trom a threephase supply l, S, T, While the outer windk ing' Ais a two-pole winding with a star con-- nection 48, and with terminals 7, e t', through which it is adapted to be exc ted loy direct current. This winding is excited under the conditions indicatedv by direct current from a source 0,k One terminal g of the source is connected through switches at 26 in parallel to the terminals s and t, while the other terminal info-t' the source is connected to terminal fr. The direct currents therefore flow in parallel through two phases of the winding, and. out througlrthe third phase, while they Value of the current in the first two phases is half of that iu the third phase. i The resultant values ofthe currents are indicated by the figures and l beside the hars in the winding, and

loe seen that they produce a symmetrically distributed -pole tieid. Pairs of windings such as are shown in Figure 9 may be used on the stator in any cL therefore where the machine is required to run at cascade speed, and also at the speeds corresponding to the basic pole numbers.

Vfl .ever a machine is required to open ate :u one speeds corresponding' to the two basic pole numbers only, a winding is preierably employed on the stator ot' the type indicated in Figures l() to l2. This winding is arranged as a parallel mesh winding, as seen in Figure 12, but the mesh connections are adapted to be opened out and changed to star connections tor operation at another pole numlier, as in Figure 11. The connections of Figure ll are those tor the lower speed, indicated as the i-pole speed, while Figure 12 shows the connections for the higher speed indicated as the Q-pole speed. in Figure l() is shown a pole changer with connected contacts Q7, Q8 and 29, adapted to connect thc coils il and 10, 6 and 9, and 2 and 5 respectively, to the three-phase terminals il, S, and T; while connected contacts 33 join together the middle mesh points 1G, i7 an i8 in star. The winding thus bef. parallel double star winding when acts shove el" in the pole changer are in operation and when the connections are made in Fioure '11. ldlhen the confacts alcole 2l) in thc pole changer are in oper tion on the other hand, coils 9 and l0. l and 5 and 6, are connected by pairs of contacts 30, 31. 32, while other pairs of contacts connect the three-phase supply terminals ll, Fa, T, to the tappings 13, 14, 15, respectively, and thc result in this case is a Q-pole field., as in Figure 12. The crosses and dots in the circles representing" the bars in Fieure .l0 indicate the flow of currents for -pole working, while the crosses and dots outside thebars indicate the 'flow oi. curro ts :For i-pole woricing.

Relerrino now to Figure 13, a complete diagram will he ot a machine adapted to operate as a synchronous motor at three speeds, assumed to tS-pole (cascade). llpole and -polc speeds respectively. The rotor winding' is indicated hy a diagram corresponding to that ot Figure 2, with its coils numbered l-ll, while the stator is indicated by two star connected windings having terminals o', l), c and. d, e, f respectively. For alternating' current excitation the stator windings are adapted to he connected to thc terminals ot three-phase supply l. S, T, our/h chan .ovcr switches 51. whereby h enncr die 's-pole or the .i3-pole winding can he excited by alternatingA current, or one he excited by A. (l, through terminals d, e, y, produce the one basic pole number (the il-nole `eidu while the other winding is 3:-

't' hy direct current from the' source o to are needed., is the -poe inciucion motor connecioris are the seme es he synchronous connections. @n moving' from il ehe generator 0 is brought into circu'iJ :ifer the short-circuit, has been broken hy i-on'aci's il moving out of zicioii. Slip rings .i and .T are comieced to one terminali ,7L of hc geoereior through resistzmces '36, 3T. which are cui; out (hiring starting. while :rii the other siip rings ere connected in parallel to termirra g through resisziiices 35. which ifrealso cui mit during starting.

TWhen the machine required rio operaie ai he cascade speed and one other fige-ec'L only, he arrangement can be siiiipiiieri is i Figure 14;; Firstly, the `windings o stator may he of the type see 'forth iii iriish pzi'ent specification No. 24838 of ii! i or 35H3 of i915. and such windings are i (iiceied diagraii'imaicaiiy ai he 'top of igure 14. The three-phase Windiri-"s :c current through erminziis R, S. T., Whiie direct currentfor produc'ng 'he other basic pcie number is introduced et he rieutr p., Q of the LL-poie Winding. ."he. poile charge has fewer comrades. ami oiiiy three 34.-, 35a 35, are needed, of wi eriri permeiienty cormecieri ro o. si 'ri rire igure the connections here changed so as to iihisraze ehe com siip rings 3 ilo and 5 to 9 `for purposes es in Figures 'i une?. l1 is now comiecied to the ief-nan resistance 34, slip ring 9 '5;0 and l io 36. The nher slip rings 3. 5 si connected eo conecs in the corrrof Varying their connections th brushes 14 and 15. As he synchronizing resis-e-.rice m musi still ne connece 'to ii. ii; is noi; connected to brush i3 one riireeiy *ce siip rings 1i. in the pole changer e* in G-lgoie position, the. gerxeroioriermirmis o, ii, are connected ro he star poiiis y2., y., in the size tor winding. .The starting and synchronizing contars iii coiumns to iV in *the -poe portion oi the conroicr 11i make lihe same circuiv comiecions hosem :ie iii i resporifiingf coiumris of iio con @iler re i3, eri/.tem ihrer. Where couific. v

vre cosmesi-eci in iiigjur cireuiro' siro rings l :ino T., of Siip rino' "i to brush i5 is cf purpose ir. Y@crire i4. For fsgme .-he change pcie swich is por ro poso, 1 in which generator rermiiizii ii. conm-cited 'to slip ring' @mi gf is coiricceii io sho ri: h i. through 25% emi resisamce 33?;v which cui; out sariofg. The eoiitro'iier m in he fi-gioie starting posiions shori circiiis geierzior' ermiriais 9' and .72., es he ore, :imi coiiriecs the slip rings 5%, 5 and 7 so isies ifi, 13 and. i5. enfui so io Ehe 'rcsiszires coi nec'ted ifo the opposite ter and l Miese ms@ respccireiy to wimiii'ig'.

ences Sli, 353 :imi are cut out by movimg Sche hrusiie 11, 'i5 to the iet as the me chine speeflt ,ed synchronous spee is ihiis ncfiri'v nziinei.; The conroiier now moved to iosiiori H in the e-pole coiurim, throwing irro circui the generator o the short-f; circui'4 "ahrough contacts 4G is broken. The machine new comes into synchronism, emi .fineiir when ihe coiroiier is moi/'eci to posiiioii Hi siig ring 3 is conneced directly rhroug'h brush. L3 "Lo il. anc slip ring hrough hrush 1% io 9. rhis completes 'ehe @tions @ending v *co Figures "i ll is ieri the machine is required i0 operaie iwo hasic pois numbers only, the conroiier is much simpiificd as indicated in figure i5. The stsi'or Winding may he as sinned io be of 'hc ivpe shown in Figures 10 to i2, hoi 'for convenience two separae windings are shown, :adapted to he corineced ihr 'ough change-over swiiches 45 ibo the ily ermimiis Ei. Si. T. iivided resist- 36. Si' wifi ierminais L', Z, have again io oe used 21s in igure 13. imi other connecons are sin'ipinici. Resistance icriiiinzii is comiecefi :iemzmeii'cij7f '0 the generator ermumi Fa. The pcie changer mereijr re i; in the column to conuires mvo come.' eci, resistance termimii Z to rho gencrzr'ior crmimii f/. The sziriirig und synchroiiiiairig corri-nets in conroiier w may make the some eomiectioiis in Lx--gr ie starting as in Figure le, but :in '.iddiioiis pair of coimece conf'mcs (5 is proif'iiic@ Vfor connecting the midpoiiis m. :ami fn. o resisimces 34, in rzirrsition 'from position H o HI. so hm'; there may he no coiiipiee break in changing' over ihe siip ring' connections. The (i5-poi@ connections are che same :is in Figure 13, except hat in the pois changer. is sufi f1y are aireziriy corrnectcd1 one cominci is saved.

li-.ihough the invention has been described as if the windings which :1re connected in cascade or 'o which direct current is supoiieii for synchronous working with 'the ower ,wie iiiiiiiwrs. were to he 'ihe rotor wiiiiiiiffs :iii have iheir terminali?, Corr Buried 'm s rei i` Wiii he zipper-eri?, hisi sucia wm i fore dcscriifeii, yet ii', er/.ii .on iziiricrsioofi ihm'. iiE :i machine is Ieqiiire izo rim :iii possibi@ speeds, it rioY s i'i'izii o rake olii :iii 'the termiriis siip rings. but some of hem curi he :wronged to intercomncci'oii. through mternai resist :mees which can be cui', by arrzingeninnis of a, known type during the running of Mie machine.

In Conclusion, it must be clearly unde Stood that though 2, 4; and (i noirs have, been referred to in the examples, the busi@ pole numbers used in przicce will generally be 4 and 8,l with a cascade speed corresioniling t0 12 poles if required, 0r olier larger pole numbers as already explained. Machines constrizced as liereinbeiore set orrli can lie used :is generators insiemi of nin'nrs, in which case oi Course Some of `die siip rings Whose connections; :ire chung-acl 'For starring' as u motor will noiy lbe needed becsiuse ih@ generator will be driven positively. in generator for example lio operaie :it lili@ pole and Q-pole requencinsi, unl;Y 'iirer Him ring-s will be needed, viz. numbers l und "e,

. and :i hird slip ring;- inferi'fonnor ng all ol" the erlninals 3, 5, and il. Then .n ill@ L4#pole frequency the tQrniinnl-:s i' #im fi): C, generator :ire cominci/eri 'l and 4, ind the roor circuits correspond. to Figure i3 with 22 and 23% Connecisrl. Ai; Z-pols 'frequency iie generator is Conneed it nn@ orininnl to both l and i', and at oilier to "die ihirii Slip ring. The ternir: roor Winding and stator Winding are ('oni'union' to distinguish the two windings on @ne sop- :rnte parts of tho nia/inno7 and aree used in the claims which 'follow to (losignui'c iii@ windings hersinbe'for@ roivrreli 'to by ''iiose grins, but i must lio nmlersood 'limi if lle Stationary and rntaing parts of lie machine are inferclmnged, *die terms :ire sfill intended to designate the Sumo n'inriing'ff. The winiiing's on 'oliv s'nor muy li@ iwophase instead ol t'lirce-piiase ii' required in any case, and ol'lier nioiiiimzions of :i simi- 1:11' Character Grin be nimh, without ilni'mrling from the snope o'l" ilie invcniion.

For the generator 0 l prcl'fir io a $eries-woiiiid nnicninc wiii intorpoli any other suitable type of gcnoru'or used.

Having' thus dfsvrilimi my ini'rn''ifm wiwi' claim :iS new unil @ansia-0 io @om ters Patent is z l. A (lynzin'ioeleclric inniiiiw .i windings 0n iii@ stniionury narrns lull produce field@ o1 two (lii'nrniii Voir niuulwf and windings on iin; i' y\'ul\':ilir pini adapted io produre iirlils ol' .ziiil 'u'o di ont polo numlwrs. no uiniiingn un onu m" @iid parts boing4 nl u type wlnwin l" i F) flow through Sonn nl" iii@ Smm) coils will (lif'ri'ent terminal munmtions 'for nrol'iuu ing fioli'ls of the tiro .iil'l'rrun pnl@ 'niuulwrfli in Combination. wir?) mouns 'For minpljfi: i dirent current ('o tim ninilingsi on lir imei, mentionedporl'inn oiZ lie umcliinr in suoli manner ns lio produc@ x'irlilS oliriliwr oi Two said "polo nunilwrs.

dynznnooler-i., u n'nuiiinu lnii'ing nuinlirrra, or in sum1;

uulingsi nn omx puri ll rofl u ce having winiiinws o n'zwisii;

field of the other of said poie numbers, means for supplying direc Curren'' o 'rho windings on the first-mentioned peri of sind machine in such manner as io produce s iieid of one of said pole numbers while connaciing the windingson @he second-montioned part oi' said machine in such manner ns io not in cascade.

G. A dynamo-electric machine haring; windings on the one part ihoreof zidupnd -o produce fields oi' two diii'ereui. pois numbers, und windings on the oiher fiori. ihm-ouf Coni prisin;r six Coils connected io ierniinnis5 wiizi. Six other coils inerifonneeiingz in mesh iii@ inner ends of said rs six coiis, conihinetion with means Jfor suppijving direc' @un rent 11o ihr windings ou he seco d-nienioned portion o'it said machin-i. in such man ner as to produfe u. .fieid of one of said poi@ numbers.

7. A windings on the on(A par produce fields of iwo diiieren Ynoie nun'ihors,y und windings on the other puri thereof comp ising six Coiis oonnociod to terminals. wiizh six other i'oiis intcrconnvcinn in mesh 'ihe inner ends of said iinsi con in combinaiion with means for suppiyi. i curi rem;y to the windings on ghe seconmnieniioned portion oi said machine in such nel' :is to produce :i Field o one of said noie numhers. und means suppiyin direc-L current io 'ho windings on ''he iir mentioned poriion of said machine in suon Ymanner us io produce :L i'ieid oi one. oi" said pois numbers whiie `c-.oni'roiing iii@ winding/s on the other portion of rho nnnhino so as "to operate in cascade.

8. dynunnx-eiecirin man? ine `inning windings on ihe on@ psriifiurrof :ldiignid o produce eids oi' two differengioie umidi/ers, und windings on ih@v oi'her ii-uri horooi' oomprisinnr six (-oiis vonnmind io iorminuis. with six other coiis inierconiui'tiiw in mosh ins inner ends of said' iirsi, sin coils., in comhimition with means for supplying: direct nurront to (the windings on ihn sonni. i-nern iioned portion of said nun-hine v such n manor :is io produce ieids of eii r or suid noir numhm's.

dyinuno-eioeirin machine having Si. dynamo-eindrio niriifiiine sin vind for s vnvhrouous working :ii n piurniiij.' :i dii i'orent speeds" said nun-hina comprising- :i siziior hearing indinffs sdiipiid to produce ieids oi' two diieroni. noie iu uirfirs. und 2L rotor hrm-iup; windings :ldap-wd 'Lo iu'odur iohis of wo diiiiren pois nunihnrs said roi'or .vindinggs iii-ing o" 'n nur ronts van fio'w ihrough such manner :is io produfe awoi'irhis o? dii- 'iieront noie numbers in Qusinde. in conihiiniu tion with nie-sns @or sunni x r ront to the windings on smid Mmor in either of two diiioront ways adupied io proiiuru (hi` fields o the respeutivo pole nunlbors.

'thereof adapted fio dynamo-niedrig. machins mi l, u, nonous working s piur diii'eren; speeds, said machine compris n* stator hearing windings adapted rio produce iicids oiE wo different pole numbers, ro'or bearing windings adapted io produce iieids oi wo dil'ierent pole numhers, sind rotor windings being of n type wherein inrreni's can 'i'iow through the ooiis thereoi' in sunh manner as fo produce wo eids o dii? ferent pole nuinhnrs in cascade, in Combinaiion wih moans for supplying direcii eurren o he windings on said roioi` in ei 'ier oi wo i'iiisreniy ways adapted io produce the iehis o i therespeetire noie numbers, means for Suppl; r; direni cnrrsn'` io e, pon ion of suid sizior windings in such ninnner :is io produce n field of one of said 'polo numbers` while Connecting said 'rotor Windings in the manner required. for operuing in essendo. Y

1l. A dynamo-eiectric machine heffing findings on ihe one par; thereof adapied 'to produce fields of two different pois numbers, und windings on ne oiher pari. inereof soienprising sin'` Coiis oonneced "co terminals., wiii izion with means for suppiying diree; our rent io the win iings on ne seCond-msnioned portion i said machine such er as produce s field of one of sfu( i numbers, 'for inerconnec nher erminsis of said inst mentioned ing: in such manner ss to provide ions Cui'i; pu'ns in sind windings through currents can for damping purposes an i'or nuinuining synchronism.

12. A dynumoeiectric machine udsoied for synchronous working` having Winnings on one puri thereof :adapted to operate. with siernziiing eurrent supplied Jehereo in such manner :is io produce fields of nither o? wo `noie numbers. and having windings on the oihfsr nari, ihrreo'i adaped to oper:` in cascade with the windings on the iirs inenoui ineniiorml pinoi" said machine s ss "io operaie wiih indurre-:i cnrrens for sini-ring" purposes n one o? he said noie nu hers,

und zidun'wi tu rhnngl'c over ihn Conneelions hipisd to runnin-t ido windings on `he C wir 3,2% adapef t0 reci-ive current producing :1

of :U1/Jiba? mmbe of poles and having ing-s on be other pari hereo'f adaptad u) permit 01 the How o" currents producing; either of Suid. ,numbers if? pole. in Combina- 21?, ion with means A or conustmg said las@ and hm'mg MHQQ adapted rgwuducing combina.- smd lust, @1' as to g ut w nei' :1s 30 pro immbars, Wim aparaat@ :1S s

*W0 @Herenk- EHI 

